Symmetry breaking in a thermal gradient

Timelapse recording (240 x) of a symmetry breaking event of approximately 300 honeybees in a complex thermal gradient. The thermal gradient spans from the ambient temperature (32.5 °C, 90.5 °F) at the center of the arena to the optimum temperature (approximately 36.5 °C, 97.7 °F) at the left and right side of the arena (local temperature is indicated by the false color representation, yellow indicates the bees' optimum temperature). The bees are released at the (cool) center of the arena and quickly move towards the two optimum areas. Initially, the majority of the bees are evenly distributed over both optimum areas, which is consistent with the fact that both areas are equivalently attractive to the bees. The aggregations in both optima are in a dynamic equilibrium, with individuals leaving and joining them at approximately the same rate. However, at a certain point (approximately 1 h in realtime, 15 s in time lapse), the right aggregation starts to slowly dissipate while the left aggregation starts to grow. This is despite the fact that the environmental parameters (thermal gradient) are kept constant throughout the experiment, so that the bees in the right aggregation do not have an actual impetus to revise their decision. Phenomena like this are frequently observed in the field of swarm research, which adopted the term "symmetry breaking" to describe a swarm's predisposition to exclusively choose one among several, equally attractive options. In our case, the observed symmetry breaking is based on the bees' striving for social interaction, which ultimately leads to a clear predominance of one aggregation as a result of an originally insignificant (probably random) bias.

Category:

Science & Technology

Tags:

• IZG
• symmetry breaking
• honeybee
• swarm
• aggregation
• collective behavior
• swarm intelligence
• thermal gradient
• swarm dynamics